Rats

You probably have heard of the nature-nurture debate. In the last decade or so, researchers have come to better understand the field of epigenetics and below is an interesting example of this in the link between stress and attachment.

Research indicated that rats raised by mothers who groom and lick them are later better able to cope with stress than pups who were infrequently licked and groomed. What seems to happen is that the brains of well-licked baby rats have been changed.

Basically, there are receptors in the brain that mop up the stress hormone cortisol, thus reducing the effect of stress on the brain. The gene that codes for these receptors is modified by the mothers’ behaviour so that the less pampered pups ultimately have fewer cortisol receptors in their brain.

The bottom line is that the attachment behaviours of the mother appears to alter the young rats’ brains so they cope less well with stressful experience. And this also affects the way the young rats subsequently treat their own babies. Nurture modifies nature. Poor attachment experiences lead to negative effects.